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G. B. GRAY- DETECTOR FOR BROKEN DOWN INSULATION.

APPLICATION FILED JAN-25.1910.

1,195,579. Patented Aug. 22, 1916.

2 SHEETS-SHEET witneooeo G. B. GRAY.

DETECTOR FOR BROKEN DOWN lNSULATlON.

, APPUICATION FILED JAN-25. 1910.

1,195,579. PatentedAug. 22,1916.

2 SHEETS-SHEET 2.

anvzntoz 'NT SAS PATENT @FFTCUE GARDNER B. GRAY, 0F PITTSBURGH, PENNSYLVANIA; ASSIGNOR, BY MESNE ASSIGN- MENTS, TO AUTOMATIC TRAIN CONTROL & SIGNAL COMPANY,.OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF DELAWARE.

DETECTOR FOR BROKEN-DOWN INSULATION.

Specification of Letters Patent.

Patented Aug. 22, 19116..

Application filed January 25, 1910. Serial No. 540,031.

ments in detectors'for broken down insulation andis designed more particularly for indicating broken down truck insulation in an automatic safety signal system for railways for which Letters Patent No. 909,083

were granted on January 5, 1909, on an applicationfi'led by me. In said system each train, or more particularly the engine of each train carried an electrically operated signal system controlled by electric circuits along the line of way in such manner that under predetermined conditions certain signals will be displayed in the engine cab in such manner as'to obtrude themselves upon the notice of the engineman on conditions dangerous to the train. Such signals'are both cautionary and positive, acting ultimately on a too close approach of the train to the danger zone to cause the stopping of the train irrespective of the volition of the engineman. The successful operation of the system depends on the maintenance of insulation at certain points and should a short circuit occur due to the breaking down of the insulation there is. at once presented a dangerous condition which must be guarded against to render the system as a whole.

operative to protect a train against other danger conditions. This is done, in accordance with the present invention, by providing a detector circuit which will become active to cause the full emergency operation of the system should there occur such a breakdown of the insulationas would render the system irresponsive to other danger conditions or to such conditions as would necessitate the display of cautionary signals.

The invention will be best understood from a consideration of the following detail description taken in connection with the accompanying drawings forming a part of this specification, in which drawings,

Figure 1 is a vertical section of a portion of a truck bolster showing the application of the invention thereto. Fig. 2 is a diagram of the engine carried circuits showing the manner of incorporating the detector circuit for a breakdown of the truck insulation.

In the aforesaid Letters Patent the system there revealed requires that the wheels or truck of a railway vehicle be insulated from the body of the same so that the operating current in the system may be taken up from the track rails while the trucks of the car are insulated one from the other against electric connection through the body of the vehicle whether the latter be a locomotive engine or a motor car such as used on electric railways. The safety of the train guarded by the system of the said Letters Patent depends upon the perfect working of such system and it therefore becomes a matter of vital importance that the insulation be not only primarily perfect but that provision be made against the effects of the breaking down of such insulation.

In Fig. 1 there is shown a means for insulating the upper truck bearings from the steel frame of a car or other railway vehicle. There is shown at 1 the upper plate or top of the bolster and at 2 the center sills, while at 3 is shown the bottom plate. Between the top plate 1 and the bottom plate 3 there is lodged a steel casting 4:. Below the bolster plate 3 is a liner plate 5 and below this liner plate is a center plate 6 forming the upper truck bearing plate. Extending centrally through the center plate 1 and also through the other superposed portions is a passage 8 for the truck center pin. Passed through the casting 6 of the truck are bolts 10 securing the several parts together.

Interposed between the lower surface of the bottom bolster plate 3 and the upper surface of the liner plate 5 is a metal plate 11 insulated from the bolster plate 3 by a sheet 12 of insulating material and from the liner plate 5 by a sheet 13 of insulating material. These several sheets are co-exten sive with the liner plate.

The passage through the lowermost plate 3 and through the casting 4 provided for the center pin is of larger diameter than the same passage through the upper bearing plate through the lowermost plate 3 and the casting a there is housed a sleeve M of insulating material, interior to which is'a metallic sleeve 15 having an internal dianheter coinciding with the diameter of the center pin passage through the liner plate 5 and the upper bearing plate 6, but this sleeve 15 is of such external diameter that when driven into the sleeve 11 the latter will be forced into firm engagement with the walls of the passage through the bolster plate 3 and casting 4. The sleeve 15 serves as a metallic bearing for the center pin thus guarding the insulating sleeve 14 from contact with said center pinand from injury thereby.

Since the bolts 10 would otherwise electrically connect the bearing plate 6 and liner plate 5 with the bolster plate 3 and parts carried thereby, the passages through these bolts through the bolster plate 3 and the casting l are sufliciently enlarged to each receive an insulating sleeve 16 in the form of a flanged bushing while interior to the insulating bushing is another bushing 17 of such diameter as to force the insulating bushings tightly against the walls of the passages provided for them. The inner ends of the bushings I? bear against the respective insulating plates 12 and 13 while passages through the metal plate 11 are provided for the bolts 10, but these passages are slightly smaller than the diameter of the bolts so that the latter are driven through the passages and therefore make good electrical contact with the plate 11.

By the means described the bearing plate 6 with the liner plate 5 and the truck engaging the bearing plate 6 are all thoroughly insulated from the bolster on the wheel side of the truck.

The cab circuits are shown in Fig. 2 in diagram, and these cab circuits may be substantially those shown in the aforesaid Letters Patent and therefore need not be retraced in this case.

The cab circuits co-act with electric circuits at block stations along the lineof way and also extending between the blocks so that the engineman is warned of the approach of the train toward dangerous con ditions, the first warning being of a cautionary nature and on the entrance of the train into close proximity of the point of danger other signals are exhibited and the train is ultimately brought to a standstill by cutting off the motive power and applying the brakes.

The system works on closed circuit, that is the parts are all held in the inactive or safety positions by the constant flow of an electric current and should from any cause said Letters Patent.

the current cease to flow the signals and control mechanism responsive to danger conditions will be actuated and the train will be brought to a standstill to be again started only after the danger conditions have ceased or have been remedied.

Included in the cab system are two relay magnets 83 and 93 the purpose of which is to control the signal circuit and the train controlling devices as set forth in the afore- The system also includes a battery 8-1 likewise referred to in the aforesaid Letters Patent. One side of the battery 8% is connected by a conductor 18 to the metal plate 11 and one side of both magnets 83 and 93 is connected by a conductor 19 to the same plate 11, this plate being shown as of exaggerated thickness in the diagram of Fig. 2. a

The cab system of the aforesaid Letters Patent also includes a reversing switch 73. One side of this reversing switch is connected by a conductor 20 to the bolster 1 or in the drawing by the reference numeral 69. In the path of the switch 7 3 at the limits of its travel are the common terminals of a conductor 77 leading to other terminals 81 and 211 in the path of armature contacts under the control of the magnet 83. Under normal conditions the magnets 83 and 93 are energized and their armatures are attracted and the several circuits causing the energization of these magnets are held closed so long as normal conditions prevail.

It is unnecessary to consider in this case the operations which take place should a train equipped with the present invention enter into cautionary or dangerous relation to another train since such conditions have been fully set forth in the aforesaid Letters Patent.

The present invention has to do solely with dangerous conditions arising from the breaking down of the insulation in the insulated parts of the circuit, and more especially in insulation between the car side and the wheel side of an insulated truck.

The general and normal circuit of the battery 84 is by way of the conductor 18 to the plate 11 and by way of the conductor 19 to the magnets 83 and 93 thence through armatures' and conductors ind contacts controlled by these magnets to the conductor 77, thence by way of the switch 73 to the conductor 20 and to the car body or the bolster 1 thence by the uninsulated truck to the track and by way of the latter to the wheel side 69 of the insulated truck and finally by way of the conductor 21and other side of the switch 73 back to the battery 8%.

Suppose that from some cause the insulation between one of the bolts 10 and either the bolster or the upper bearing plate 6 of the truck should, break down. Considering first that the insulation between the bolt and the bolster breaks down then there is established a circuit from thebattery 84 to the switch 73, thence by way of the conductor 21 to the truck member 69, thence by way of the traflic rails to the other truck member and to the bolster l and thence by the bolt 10 having defective insulation to the plate 11 and by Way of the conductor 18 back to the battery 84 thus short circuiting the magnets 83 and 93 and causing their deenergization and the consequent operation of the danger signals and the train controlling devices in a manner to stop the train all as set forth in the aforesaid Letters Patent.

If it be considered that the insulation between a bolt 10 and 'the upper bearing plate 6 should break down then there is established a circuit between the battery 84, the switch 73, the conductor 21, the truck 69, the plate 11, and the conductor 18 back to the battery 84: thus deenergizing the magnets 83 and 93 and causing the operation of the danger signals and of the train controlling devices as before. Should either of the insulating sheets 12 or 13 break down then there will be established a circuit from the battery 84 to the switch 73, conductor 21, truck member 69, plate 11, assuming that the insulating sheet 13 breaks down, thence back.

to the battery by the conductor 18, or if the sheet 12 breaks down then a circuit is established from the battery 84 to the switch 73 by the conductor 21 to the truck member 69 thence by the trafiic rails to the other truck and by the bolster 1 to the plate 11 and by the conductor 18 back to the battery 84:, in either case short circuiting the magnets 83 and 93 and causing the active operation of the signal and train controlling'devices as before.

It will be observed that in the event of the insulation in the truck structure breaking down, electric circuits which are maintained in operative condition by the insulating material become in part bridged by other electric circuits thus short circuiting other parts of the circuits and thereby establishing conditions which cause the display of danger signals and the active operation of train controlling devices thus preventing the train from moving into the danger zone with its safety appliances in an imperfect or inop-' erative condition.

What is claimed is 1. A detector for broken down insulation comprising a normally closed charged electric circuit including translating devices and members separated by intervening insulation and also including a conductor extend- ,ing through the intervening insulation sepaplate and a bolster with interposed insulation, a conductor housed in said insulation, and a detector circuit including said conductor.

5. In car truck construction, a center bearingplate and bolster carrying the same having insulation between the plate and bolster, insulated, bolts securing the center plate to its bolster, and a conducting member between the center bearing plate and the bolster and separated therefrom by the insulation, said conducting member being in electrical connection with the insulated bolts.

6. In car truck construction, a center bearing plate, a bolster carrying it, a conducting plate between the center bearing plate and the bolster, insulation interposed between the conducting plate and the said center bearing plate and the bolster, and bolts connecting the center bearing plate and the bolster and insulated from each, said bolts being in electrical connection with the conducting member between but insulated from the center bearing plate and the bolster.

7. In a system of the class described, a car truck having a center bearing plate and a bolster insulated one from the other, a conducting member between the center bearing plate and the bolster and electrically separated therefrom by the insulation and a car carried charged electric circuit including the electrical side of car controlling means and also including the center bearing plate, the bolster and the conducting member insulated from but intermediate thereof.

.8. In a car truck, the combination of a metallic part connected .to the wheels, a metallic part connected to the car, together with an intermediary metallic member and insulation, whereby the three metallic parts are insulated from each other.

9. A detector for broken down insulation comprising conducting members separated by intervening insulation, a conducting member housed in the insulation and :1 normally closed charged electric circuit including a translating device, a conductor between I ammo the source'and thetranslating device in elecmy own, I have hereto aflixecl my signature trical connection with the -housedmember in the presence of two witnesses. and another conductor between the source I GARDNER B. GRAY. and the translating device in electrical con- Witnesses: 5 nection with said se arate d members. P. THURBER, In testimony that claim the foregoing as E. N. BLA'IT. 

